About WebM to MP4
Screen and browser recordings are often WebM, which iPhones, PowerPoint, and some editors handle poorly. MP4 is the safe choice.
WebM video (VP8/VP9) is re-encoded to H.264 and audio (Opus/Vorbis) to AAC. WebM files using the AV1 codec cannot be decoded by this FFmpeg build.
The FFmpeg engine (about 31 MB) downloads the first time you convert and is then cached by your browser. Files up to about 100 MB are supported because everything runs in browser memory.
WebM vs MP4
| WebM | MP4 | |
|---|---|---|
| What it is | Web-focused Matroska variant | MPEG-4 Part 14 container |
| Typical codecs | VP8 or VP9 video (sometimes AV1), Vorbis or Opus audio | H.264 or HEVC video, AAC audio |
| Common use | Browser recordings, web video | Plays almost everywhere |
How to do it
- 1
Drop a WebM file into the converter above (already set to MP4).
- 2
No settings needed.
- 3
Tap Convert, keep the tab open until it finishes, then download the MP4.